regexp_replace.md

Function

  regexp_replace — replace regular expression matches in a string

Synopsis

regexp_replace(s: string, re: string|regexp, new: string) -> string

Description

The regexp_replace function substitutes all characters matching the regular expression re in string s with the string new.

Variables in new are replaced with corresponding matches drawn from s. A variable is a substring of the form $name or ${name}, where name is a non-empty sequence of letters, digits, and underscores. A purely numeric name like $1 refers to the submatch with the corresponding index; other names refer to capturing parentheses named with the (?P<name>...) syntax. A reference to an out of range or unmatched index or a name that is not present in the regular expression is replaced with an empty string.

In the $name form, name is taken to be as long as possible: $1x is equivalent to ${1x}, not ${1}x, and, $10 is equivalent to ${10}, not ${1}0.

To insert a literal $ in the output, use $$ in the template.

Examples:

Replace regular expression matches with a letter:

echo '"-ab-axxb-"' | super -z -c 'yield regexp_replace(this, /ax*b/, "T")' -

=>

"-T-T-"

Replace regular expression matches using numeric references to submatches:

echo '"option: value"' |
  super -z -c 'yield regexp_replace(this,/(\w+):\s+(\w+)$/,"$1=$2")' -

=>

"option=value"

Replace regular expression matches using named references:

echo '"option: value"' |
  super -z -c 'yield regexp_replace(
                 this,
                 /(?P<key>\w+):\s+(?P<value>\w+)$/,
                 "$key=$value")
  ' -

=>

"option=value"

Wrap a named reference in curly braces to avoid ambiguity:

echo '"option: value"' |
  super -z -c 'yield regexp_replace(
                 this,
                /(?P<key>\w+):\s+(?P<value>\w+)$/,
                "$key=${value}AppendedText")
  ' -

=>

"option=valueAppendedText"